import { useCallback, useState } from "react";

import {
  downloadMarkdownAsDocx,
  downloadMarkdownAsPdf,
  type DocxOptions,
  type PdfOptions,
} from "./converter";

/**
 * Markdown 下载 Hook 配置选项
 */
export interface UseMarkdownDownloadOptions {
  /**
   * 下载开始时的回调
   */
  onDownloadStart?: (format: "docx" | "pdf") => void;
  /**
   * 下载完成时的回调
   */
  onDownloadEnd?: (format: "docx" | "pdf") => void;
  /**
   * 下载失败时的回调
   */
  onError?: (error: Error, format: "docx" | "pdf") => void;
}

/**
 * Markdown 下载 Hook 返回值
 */
export interface UseMarkdownDownloadReturn {
  /**
   * 当前下载状态
   */
  isDownloading: "docx" | "pdf" | null;
  /**
   * 下载为 DOCX
   */
  downloadAsDocx: (
    markdown: string,
    filename: string,
    options?: DocxOptions,
  ) => Promise<void>;
  /**
   * 下载为 PDF
   */
  downloadAsPdf: (
    markdown: string,
    filename: string,
    options?: PdfOptions & {
      resolveAssetUrl?: (rawPath: string) => string | null | Promise<string | null>;
    },
  ) => Promise<void>;
  /**
   * 是否可以下载（没有正在进行的下载）
   */
  canDownload: boolean;
}

/**
 * Markdown 文档下载 Hook
 *
 * @description
 * 将 Markdown 内容转换为 DOCX 或 PDF 格式并下载。
 * 可在任何 React + TypeScript 项目中使用。
 *
 * @example
 * ```tsx
 * import { useMarkdownDownload } from "./hooks/use-markdown-download";
 *
 * function MyComponent() {
 *   const { downloadAsDocx, downloadAsPdf, isDownloading, canDownload } = useMarkdownDownload({
 *     onError: (error, format) => {
 *       console.error(`Failed to download as ${format}:`, error);
 *     },
 *   });
 *
 *   const handleDownload = () => {
 *     downloadAsDocx("# Hello World", "document");
 *   };
 *
 *   return (
 *     <button onClick={handleDownload} disabled={!canDownload}>
 *       {isDownloading === "docx" ? "Converting..." : "Download DOCX"}
 *     </button>
 *   );
 * }
 * ```
 */
export function useMarkdownDownload(
  options: UseMarkdownDownloadOptions = {},
): UseMarkdownDownloadReturn {
  const { onDownloadStart, onDownloadEnd, onError } = options;

  const [isDownloading, setIsDownloading] = useState<"docx" | "pdf" | null>(
    null,
  );

  const downloadAsDocx = useCallback(
    async (markdown: string, filename: string, options?: DocxOptions) => {
      if (isDownloading) return;

      setIsDownloading("docx");
      onDownloadStart?.("docx");

      try {
        await downloadMarkdownAsDocx(markdown, filename, options);
      } catch (error) {
        onError?.(
          error instanceof Error ? error : new Error(String(error)),
          "docx",
        );
      } finally {
        setIsDownloading(null);
        onDownloadEnd?.("docx");
      }
    },
    [isDownloading, onDownloadStart, onDownloadEnd, onError],
  );

  const downloadAsPdf = useCallback(
    async (
      markdown: string,
      filename: string,
      options?: PdfOptions & {
        resolveAssetUrl?: (rawPath: string) => string | null | Promise<string | null>;
      },
    ) => {
      if (isDownloading) return;

      setIsDownloading("pdf");
      onDownloadStart?.("pdf");

      try {
        await downloadMarkdownAsPdf(markdown, filename, options);
      } catch (error) {
        onError?.(
          error instanceof Error ? error : new Error(String(error)),
          "pdf",
        );
      } finally {
        setIsDownloading(null);
        onDownloadEnd?.("pdf");
      }
    },
    [isDownloading, onDownloadStart, onDownloadEnd, onError],
  );

  return {
    isDownloading,
    downloadAsDocx,
    downloadAsPdf,
    canDownload: isDownloading === null,
  };
}

// 导出转换函数，供非 React 环境使用
export { downloadMarkdownAsDocx, downloadMarkdownAsPdf } from "./converter";